SARS-CoV-2: Virus that causes Covid-19 is airborne, acknowledges US CDC

US CDC, in the science brief part of its public guidelines on Covid-19, has revised the listed modes of SARS-CoV-2 transmission to include the possibility of the virus being airborne. A report in the Lancet medical journal in April dismissed the predominant scientific view that the virus is not an airborne pathogen.

Since the beginning of the Covid-19 pandemic last year, most researchers and experts have held on to the view that Covid-19 was not airborne and transmission took place only through droplets of respiratory fluids of an infected person. This view has now shifted with virologists and immunologists suggesting that transmission on such a large scale could not have happened unless the virus was airborne.

In its latest brief, the World Health Organisation (WHO) also said, "Current evidence suggests that the virus spreads mainly between people who are in close contact with each other, typically within 1 metre (short-range). A person can be infected when aerosols or droplets containing the virus are inhaled or come directly into contact with the eyes, nose, or mouth."

Researchers in Sri Lanka also claimed to have detected a new variant of coronavirus that they said could remain airborne for nearly an hour. "The new strain is airborne, the droplets can remain airborne for nearly an hour," one of the island's leading immunologists, Neelika Malavige told the media in April of this year.

In its science brief, the US Centers for Disease Control and Prevention (CDC) said while the understanding of how the transmission of SARS-CoV-2 occurs has shifted, the ways to prevent infection have not.

This means that the use of face masks (double masking), hand hygiene and social distancing remain the best ways to prevent infection even after getting vaccinated against Covid-19.

Two #masks can increase your protection against the #coronavirus. #DoubleMasking has been recently corroborated by the US CDC as a stronger barrier against the virus than a single mask. Here are the DOs and DON'Ts of double masking: #DIU #MaskUp #Covid19 #RE pic.twitter.com/N3iomgvDIG — IndiaToday (@IndiaToday) April 27, 2021

"Modes of SARS-CoV-2 transmission are now categorized as inhalation of virus, deposition of virus on exposed mucous membranes, and touching mucous membranes with soiled hands contaminated with virus," said the CDC.

According to the top US medical body, exposure to respiratory fluids carrying the coronavirus is the principal mode of transmission. This can happen in three ways:

• Inhalation of very fine respiratory droplets and aerosol particles
• Deposition of respiratory droplets and particles on exposed mucous membranes in the mouth, nose, or eye by direct splashes and sprays
• Touching mucous membranes with contaminated hands

What are respiratory fluids?

Respiratory fluids are droplets people release during exhalation. It is through these droplets that an infected person can transmit the virus.

According to the CDC, the largest droplets settle out of the air rapidly.

However, the smallest, very fine droplets and aerosol particles formed when these droplets rapidly dry, are small enough that they can remain suspended in the air for minutes to hours.